Medical or nondestructive testing (NDT) ultrasound imaging applications have a growing demand for more sophisticated echo signal beamforming in the receiver frontend circuit. This may be necessary to generate high resolution acoustic images. The conventional ultrasound echo multiplexing circuits usually have an array of high-voltage analog switches (MUX) in between a transducer probe PZT array and multiple Tx/Rx channel circuitry.
These circuits have several limitations. These circuits first require Tx and Rx channel having an equal number of channels. Second, the transmitting pulses are generally high voltage and the receiving echo signals are generally low voltage. However, both signals have to pass through the same MUX. This requires that every MUX switch must have a low on-resistance when its turned on, and that it can withstand high voltage when it is turned off. These requirements make the cost of the MUX switch very high.
Therefore, it would be desirable to provide a circuit and method that overcomes the above problems. The circuit and method would be able to switch the echo signal only to overcome the above problems.